Laser-Assisted Versus Mechanical Recanalization of Femoral Arterial Occlusions Jonathan M. Tobis, MD, Robert Conroy, MD, Larry-Stuart Deutsch, MD, Ian Gordon, MD, PhD, Junko Honye, MD, PhD, Jeff Andrews, BA, Glen Profeta, BS, Sherrie Chatzkel, MD, and Michael Berns, PhD
A randomized clinical trial was performed to test the hypothesis that a laser-heated probe is superior to standard techniques to reopen occluded femoral arteries. Twenty patients were treated with a standard guidewire and balloon dilation method. In a second group of 20 patients, the laser probe was initially used as a nonheated mechanieal device. If the probe was unsuccessful in mechanically reopening the artery, an Argon laser was activated to heat the probe. The mean length of occlusion was 15.9 f 10.3 cm. The success rate for the laser probe was 15 of 20 (75%), which was not significantly different from the standard method, 19 of 20 (95%). Most of the success in the laser-probe group was due to the probe’s mechanical properties. The laser probe was successful as a cold, mechanical device in 13 of 15 (87%) arteries. It was necessary to heat the probe in 5 patients. When heated, the laser probe assisted recanalization in 2 but perforated the artery in 3 cases. The results of thii randomized trial do not support the hypotheses behind the use of the thermal laser probe. The laser probe functions primarily as a mechanical device. The thermal activation does not significantly improve the success rate without increasing the risk of perforation. This small additional benefit does not justify the large cost of current thermal laser devices. This controlled study also demonstrates a higher success rate in long occlusions than previous reports of mechanical balloon recanalization. This is due to a combination approach of retrograde and anterograde probing of the occluded segment. (AmJ Cardiol 1991;68:1079-1086) From the Divisions of Cardiology, Radiology and Surgery, University of California, Irvine, Long Beach Veterans Administration Hospital, and Beckman Laser Institute, Orange, California. This study was sup ported by Grant RR01192 from the National Institutes of Health, Bethesda, Maryland, and Grant NOO014-90-C-0029 from the Oflice of Naval Research, Arlington, Virginia. Manuscript received April 15, 1991; revised manuscript received and accepted June 17,1991. Address for reprints: Jonathan M. Tobis, MD, Cardiac Catheterization Laboratory, University of California, Irvine Medical Center, 101 City Drive South, Route 81, Orange, California 92613-4091.
he use of laser energy to ablate atherosclerosis and assist peripheral or coronary angioplasty has caught the imagination of the medical profession and the patient population. As of June 1990, it was reported that 30,000 cases of laser-assisted thermal angioplasty had been performed.’ In response to early reports of a high perforation rate with bare fiber catheters,2>3 most of the procedures have been performed with a fiberoptic conduit with a metal cap at the distal end.4l5 This device uses laser energy to heat the metal tip which produces a thermal-tissue interaction to perform the arterial recanalization. The theoretical assumptions of the mechanism of action of the laser-assisted thermal probe are: (1) that it reopens occluded arteries by tracking the original lumen; and (2) the thermal energy ablates atherosclerotic tissue, thereby reducing the mass of atheroma which helps to recanalize the artery and also improve the long-term patency rate.‘j Despite these theories and the high rate of use of these Food and Drug Administration approved devices, there has been no randomized clinical trial to demonstrate any benefit of the thermal probes over standard techniques for arterial recanalization. The purpose of the present study was to conduct a randomized clinical trial to test the hypothesis that (1) the laser-assisted probe, either as a mechanical or thermal device, is superior to standard guidewire and catheter techniques currently in use; and (2) there is an additional benefit to using thermal energy to recanalize peripheral arteries compared with the mechanical effect of the probe.
T
METHODS Patient selection: Patients were recruited to participate in this study if they had symptoms of claudication and angiographic evidence of an occluded superficial femoral artery. Only patients with complete occlusions on angiography were included in this protocol; stenotic lesions were not treated by the laser probe and were excluded from this study. In addition, the length of the occlusion or the degree of calcification was not used to exclude patients. At least 1 patent tibia1 vessel for runoff was a criterion for inclusion. The primary end point for a successful result was recanalization of the occludcd segment of artery with angiographic evidence of direct flow between the proximal and distal lumens. LASER ANGIOPLASTY
1079
FIGURE 1. Representation of randomized trial treatment protocol. SFA = superficiil femoral artery.
IF UNABLE
There were 40 patients (36 men and 4 women, mean age 65 years (range 42 to 83) who participated in this study. All patients had been cigarette smokers (1 to 4 packs per day). Ten had diabetes mellitus, but only I required insulin. All patients had symptoms of claudication for a period of 3 months to 17 years before entering the study. Five of the patients had pain at rest, but no patient had gangrene or an active skin ulcer due to vascular insufficiency. Baseline clinical evaluation, including Doppler-measured systolic occlusion pressure in the leg and arm, was performed in all patients. The patients signed the institutional consent form approved by the Human Subjects Review Committee. Study protocol: Patients were randomly assigned by a computer-generated rotation to 1 of 2 treatment protocols: a standard guidewire method or the laser probe method. In the patients assigned to the standard mechanical guidewire group, a variety of 0.035 inch guidewires (Cook, Rosen, straight) were inserted
FIGURE catheter blunted menfs.
1080
2. Magnified view of the metal capped fiberoptic used in this study. The 1.5 mm diameter tip has a shape to facilitate penetration of occhded arterial seg-
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
TO PASS:
through a 6Fr or 7Fr plastic catheter (Van Andel, multipurpose, or Tot-con pull-down catheter). The area of obstruction was probed with the guidewire under fluoroscopic control and the catheter was advanced over the guidewire as it progressed distally through the arterial occlusion. If the operator felt that the attempt at mechanical recanalization was no longer feasible, then the patient could cross over to the laser-assisted method. In the patients assigned to the laser protocol, the laser probe was initially used as a cold, mechanical device without turning on the laser. The outline of the randomization protocol is seen in Figure 1. The laser probe used in this study was a 1.5 mm diameter Laserprobe model PLR-plus (Trimedyne, Inc., Santa Ana, California) (Figure 2). Two different laser generating systems were used: An Argon laser, Optilase model 900 (Trimedyne Inc, Santa Ana, California) or a KTPYAG laser model 532 (Laserscope, San Jose, California). The laser probe was inserted through a TuohyBorst adaptor Y connector (to prevent backbleeding and permit contrast injections) and was passed alone through the introducer sheath or through a 7Fr Judkins right coronary angioplasty guiding catheter to provide support for the laser probe. The guiding catheter tip was steam-heated to straighten the distal curve. Under fluoroscopic guidance, the laser probe, without activating the laser, was pushed into the occlusion with increasing force which was subjectively determined by the operator. The same operator manipulated the laser probe in all patients while mechanical guidewire manipulation was performed primarily by the interventional radiologists. After the laser probe advanced 3 to 5 cm, contrast was injected to determine if there was a perforation or if the catheter pathway was still within the boundary of the artery. The laser probe was advanced in this manner until the obstruction was recaOCTOBER
15, 1991
nalized, the artery was perforated, or the operator subjectively felt that further mechanical force was unlikely to be successful. If successful recanalization occurred, the laser probe was withdrawn and an 0.035 inch guidewire was advanced through the new channel. Balloon dilation angioplasty was then performed in all cases with an appropriately sized balloon (4 to 7 mm diameter). If recanalization was unsuccessful with the laser probe as a cold, mechanical device (and if a perforation had not occurred), then the laser was turned on at 10 to 12 W to heat the metal-tipped catheter to approximately 2OO’C. Gentle pressure was maintained on the heated-tipped catheter at the level of occlusion for 5 to 10 seconds. If no forward progress was achieved, the laser was turned off and the catheter was moved back and forth rapidly for 3 seconds to permit the heat to dissipate without tissue agglutination around the metal tip. The heated tip catheter was advanced intermittently in this manner until recanalization was achieved or the artery was perforated. There were 14 arteries where the procedure was performed in a retrograde direction from the popliteal artery.7 In these 14 arteries, the residual patent lumen of the proximal superficial femoral artery was 30 cm), or they may perforate externally. (Reprinted with permission from Cardiovascular Reviews and Reports, Im.)
TABLE
I Comparison
of Clinical
Trials to Recanalize
Author
Technrque
Zeitler 1980 Marhn 1981
Mechanical
Krepel 1985 Hewes 1986
Balloon
Morganstern 1977-80 1981-88
Balloon Balloon
Occluded
Balloon
Balloon
Total
Balloon or laser probe Laser probe Heated
Tobis 1989 McGowan 1988 Leachman 1989 Tobis Present 1991
Laser probe Heated Laser probe Heated Laser probe Heated Balloon
Femoropopliteal
Arteries Percent Primary Success
1 Year Patency of Pts. with 1” Success (%I
No. of Arteries
Occluded Length (cm)
304 133 46
82 53 76
NA NA 57
18 19 18 10 13 59 46
10 NA (mean 4 cm in 1” success group) 3 l-3 4-7 >7 NA l-20
89
93
26
83 74
50 81 100 91 82 NA
70
l-10
91
NA
86 69 100 70 66 73 67
NA NA 93 76 58 72 40
5.6 2 3.1
93
NA
20
< 10 > 10 14.2 + 6.9
80 50 95
NA NA 60
20
16.6
75
50
Thermal Levy 1989 Sanborn 1988
Superficial
14 13 17 37 53 Total 107 17 15 Total 117
Angioplasty
Studies NA NA 7 9.6 10.9
t 7.2
series Laser probe Cold (15) Hot (5)
t 9.7
NA = not available.
,
83% for occlusions 15 to 45 cm long, with an overall mechanism of recanalization proceeds along the perimprimary success rate of 85%. It is difficult to compare eter of the plaque, was used advantageously. Instead of different clinical studies because some reports combine terminating the procedure once the dissection plane was patients who have stenoses with those who have com- observed, it was used to burrow around the plaque until plete occlusions. In addition, the length of occlusion or the distal lumen could be reentered by tearing into it how the lengths are subdivided varies between the re- from the perimeter. It is ironic that in the attempt to ports. Some of the frequently cited clinical trials for find a better method than mechanical recanalization, recanalization of occluded superficial femoral arteries our experience with laser-assisted thermal angioplasty are presented for comparison in Table I for both me- lead to refinements in technique that improved the rechanical and thermal angioplasty. sults with standard mechanical balloon angioplasty. Earlier nonrandomized laser studies used historical This experience reemphasizes how the use of historical control groups to claim that mechanical balloon angio- control groups may be misleading. plasty has a limited primary success rate in occlusions This randomized trial demonstrates that the laser>3 cm and certainly >7 cm. However, a recent re- assisted probe is not superior to the results with stanport l l and the current study demonstrate a higher rate dard guidewire manipulation to reopen occluded superof primary success using mechanical guidewires and ficial femoral arteries. In addition, this study indicates supportive catheters. The high rate of success in the that the predominant effect of the laser probe appears present series of recanalizing long occluded segments of to be due to the mechanical component of the probe the superficial femoral artery is attributed to the alter- and not laser-induced heat. The blunted bullet-shaped native approaches used: either retrograde from the pop- contour of the laser probe was well designed to peneliteal artery or the combined anterograde and retro- trate atheroma. This penetration occurs around the obgrade punctures. In addition, the observation that the struction between the internal elastic membrane and LASER ANGIOPIASTY
1085
the plaque. Once in this dissection plane, it is more likely that the thermally active 2OO’C metal tip will perforate laterally through the thin media and adventitia. Thermal activation of the probe added successfully to the mechanical effect of the device in only 2 of 20 (10%) patients assigned to the laser group. This meager additional benefit does not appear to justify the large cost of current laser devices. The fact that 30,000 cases of laser-assisted thermal angioplasty have been performed without a randomized trial raises serious concerns about the scientific foundation on which decisions of treatment are made in interventional procedures with new devices.r2-l4
REFERENCES 1. Moretti M, Pearson T (eds.). Patient Data Supports Laser Angioplasty Efficacy. Medical Laser Industry Report (suppl) April 1990: l-4. 2. Lee G, Ike& RM, Chan MC, Lee MH, Ring JL, Reis RL, Theis JH, Low R, Bommer WJ, Kong AH, Hanna ES, Mason DT. Limitations, risks and complications of laser angioplasty: a cautious approach warranted. Am I Cardiol 1985;56:181-185. 3. Lee G, Ike& RM, Theis JH, Chan MC, Stabbe D, Ogata C, Kumagai A, Mason DT. Acute and chronic complications of laser angioplasty: vascular wall damage and formation of aneurysms in the atherosclerotic rabbit. Am d Cardiol 1984;53:290-293.
1086
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
4. Sanborn TA, Faxon DP, Haudenschild CC, Ryan TJ. Experimental angioplasty: circumferential distribution of laser thermal energy with a laser probe. J Am CON Cardiol 1985;5:934-938. 5. Lee G, Ikeda RM, Chan MC, Dukich J, Lee MH, Theis JH, Bommer WJ, Reis RL, Hanna ES, Mason DT. Dissolution of human atherosclerotic disease by fiberoptic laser-heated metal cautery cap. Am Heart J 1984;107:777-778. 6. Cumberland DC, Sanborn TA, Tayler DI, Welsh CL, Guben JK, Moore DJ, Greenfield AJ, Ryan TJ. Percutaneous laser thermal angioplasty: initial clinical results with a laser probe in total peripheral artery occlusion. Lancet 1986;l: 1457-1459. 7. Leachman R, Avedissian MG, Krajcer Z, Angelini P. Transluminal laser angioplasty of the femoropopliteal circulation by use of a percutaneous poplitcal approach. Am J of Cardioi 1989;64:106-108. 8. Tobis J, Smolin M, Mallery J, MacLeay L, Johnston WD, Connolly JE, et al. Laser-assisted thermal angioplasty in human peripheral artery occlusions: Mechanisms of recanalization. d Am CON Cardiol 1989;13:1547-1554. 9. Sanborn TA, Cumberland DC, Greenfield AJ, Motarjeme A, Schwarten DE, Leachman SR, et al. Peripheral laser-assisted balloon angioplasty. Arch Surg 1989;124:1099-1103. 10. Tobis JA, Miranda CP, Deutsch L-S, Griffith J, Gessert J, Bergman A, Berm M, Henry WI. The mechanism of peripheral recanalization by laser-assisted thermal angioplasty: confirmation by intravascular ultrasound. AJR 1990;155: 1100-1102. 11. Morgenstern BR, Getrajdman GI, Laffey KJ, Bixon R, Martin EC. Total occlusions of the femoropopliteal artery: high technical success rate of conventional balloon angioplasty. Radiology 1989;172:937-940. 12. Strandness DE, Barnes RW, Katzen B, Ring EJ. Indiscriminate use of laser angioplasty (editorial). Radiology 1989;172:945%946. 13. Society of Cardiovascular and Interventional Radiology. SCVIR position statement on thermal laser angioplasty. (editorial response) Radiology 1989; 172944. 14. Sanborn TA, Greenfield AJ. Peripheral laser angioplasty: need for organized clinical trials. (editorial response) Radiology 1989;172:943.
OCTOBER
15. 1991
A randomized clinical trial was performed to test the hypothesis that a laser-heated probe is superior to standard techniques to reopen occluded femoral arteries. Twenty patients were treated with a standard guidewire and balloon dilation method. In a second group of 20 patients, the laser probe was initially used as a nonheated mechanieal device. If the probe was unsuccessful in mechanically reopening the artery, an Argon laser was activated to heat the probe. The mean length of occlusion was 15.9 f 10.3 cm. The success rate for the laser probe was 15 of 20 (75%), which was not significantly different from the standard method, 19 of 20 (95%). Most of the success in the laser-probe group was due to the probe’s mechanical properties. The laser probe was successful as a cold, mechanical device in 13 of 15 (87%) arteries. It was necessary to heat the probe in 5 patients. When heated, the laser probe assisted recanalization in 2 but perforated the artery in 3 cases. The results of thii randomized trial do not support the hypotheses behind the use of the thermal laser probe. The laser probe functions primarily as a mechanical device. The thermal activation does not significantly improve the success rate without increasing the risk of perforation. This small additional benefit does not justify the large cost of current thermal laser devices. This controlled study also demonstrates a higher success rate in long occlusions than previous reports of mechanical balloon recanalization. This is due to a combination approach of retrograde and anterograde probing of the occluded segment. (AmJ Cardiol 1991;68:1079-1086) From the Divisions of Cardiology, Radiology and Surgery, University of California, Irvine, Long Beach Veterans Administration Hospital, and Beckman Laser Institute, Orange, California. This study was sup ported by Grant RR01192 from the National Institutes of Health, Bethesda, Maryland, and Grant NOO014-90-C-0029 from the Oflice of Naval Research, Arlington, Virginia. Manuscript received April 15, 1991; revised manuscript received and accepted June 17,1991. Address for reprints: Jonathan M. Tobis, MD, Cardiac Catheterization Laboratory, University of California, Irvine Medical Center, 101 City Drive South, Route 81, Orange, California 92613-4091.
he use of laser energy to ablate atherosclerosis and assist peripheral or coronary angioplasty has caught the imagination of the medical profession and the patient population. As of June 1990, it was reported that 30,000 cases of laser-assisted thermal angioplasty had been performed.’ In response to early reports of a high perforation rate with bare fiber catheters,2>3 most of the procedures have been performed with a fiberoptic conduit with a metal cap at the distal end.4l5 This device uses laser energy to heat the metal tip which produces a thermal-tissue interaction to perform the arterial recanalization. The theoretical assumptions of the mechanism of action of the laser-assisted thermal probe are: (1) that it reopens occluded arteries by tracking the original lumen; and (2) the thermal energy ablates atherosclerotic tissue, thereby reducing the mass of atheroma which helps to recanalize the artery and also improve the long-term patency rate.‘j Despite these theories and the high rate of use of these Food and Drug Administration approved devices, there has been no randomized clinical trial to demonstrate any benefit of the thermal probes over standard techniques for arterial recanalization. The purpose of the present study was to conduct a randomized clinical trial to test the hypothesis that (1) the laser-assisted probe, either as a mechanical or thermal device, is superior to standard guidewire and catheter techniques currently in use; and (2) there is an additional benefit to using thermal energy to recanalize peripheral arteries compared with the mechanical effect of the probe.
T
METHODS Patient selection: Patients were recruited to participate in this study if they had symptoms of claudication and angiographic evidence of an occluded superficial femoral artery. Only patients with complete occlusions on angiography were included in this protocol; stenotic lesions were not treated by the laser probe and were excluded from this study. In addition, the length of the occlusion or the degree of calcification was not used to exclude patients. At least 1 patent tibia1 vessel for runoff was a criterion for inclusion. The primary end point for a successful result was recanalization of the occludcd segment of artery with angiographic evidence of direct flow between the proximal and distal lumens. LASER ANGIOPLASTY
1079
FIGURE 1. Representation of randomized trial treatment protocol. SFA = superficiil femoral artery.
IF UNABLE
There were 40 patients (36 men and 4 women, mean age 65 years (range 42 to 83) who participated in this study. All patients had been cigarette smokers (1 to 4 packs per day). Ten had diabetes mellitus, but only I required insulin. All patients had symptoms of claudication for a period of 3 months to 17 years before entering the study. Five of the patients had pain at rest, but no patient had gangrene or an active skin ulcer due to vascular insufficiency. Baseline clinical evaluation, including Doppler-measured systolic occlusion pressure in the leg and arm, was performed in all patients. The patients signed the institutional consent form approved by the Human Subjects Review Committee. Study protocol: Patients were randomly assigned by a computer-generated rotation to 1 of 2 treatment protocols: a standard guidewire method or the laser probe method. In the patients assigned to the standard mechanical guidewire group, a variety of 0.035 inch guidewires (Cook, Rosen, straight) were inserted
FIGURE catheter blunted menfs.
1080
2. Magnified view of the metal capped fiberoptic used in this study. The 1.5 mm diameter tip has a shape to facilitate penetration of occhded arterial seg-
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
TO PASS:
through a 6Fr or 7Fr plastic catheter (Van Andel, multipurpose, or Tot-con pull-down catheter). The area of obstruction was probed with the guidewire under fluoroscopic control and the catheter was advanced over the guidewire as it progressed distally through the arterial occlusion. If the operator felt that the attempt at mechanical recanalization was no longer feasible, then the patient could cross over to the laser-assisted method. In the patients assigned to the laser protocol, the laser probe was initially used as a cold, mechanical device without turning on the laser. The outline of the randomization protocol is seen in Figure 1. The laser probe used in this study was a 1.5 mm diameter Laserprobe model PLR-plus (Trimedyne, Inc., Santa Ana, California) (Figure 2). Two different laser generating systems were used: An Argon laser, Optilase model 900 (Trimedyne Inc, Santa Ana, California) or a KTPYAG laser model 532 (Laserscope, San Jose, California). The laser probe was inserted through a TuohyBorst adaptor Y connector (to prevent backbleeding and permit contrast injections) and was passed alone through the introducer sheath or through a 7Fr Judkins right coronary angioplasty guiding catheter to provide support for the laser probe. The guiding catheter tip was steam-heated to straighten the distal curve. Under fluoroscopic guidance, the laser probe, without activating the laser, was pushed into the occlusion with increasing force which was subjectively determined by the operator. The same operator manipulated the laser probe in all patients while mechanical guidewire manipulation was performed primarily by the interventional radiologists. After the laser probe advanced 3 to 5 cm, contrast was injected to determine if there was a perforation or if the catheter pathway was still within the boundary of the artery. The laser probe was advanced in this manner until the obstruction was recaOCTOBER
15, 1991
nalized, the artery was perforated, or the operator subjectively felt that further mechanical force was unlikely to be successful. If successful recanalization occurred, the laser probe was withdrawn and an 0.035 inch guidewire was advanced through the new channel. Balloon dilation angioplasty was then performed in all cases with an appropriately sized balloon (4 to 7 mm diameter). If recanalization was unsuccessful with the laser probe as a cold, mechanical device (and if a perforation had not occurred), then the laser was turned on at 10 to 12 W to heat the metal-tipped catheter to approximately 2OO’C. Gentle pressure was maintained on the heated-tipped catheter at the level of occlusion for 5 to 10 seconds. If no forward progress was achieved, the laser was turned off and the catheter was moved back and forth rapidly for 3 seconds to permit the heat to dissipate without tissue agglutination around the metal tip. The heated tip catheter was advanced intermittently in this manner until recanalization was achieved or the artery was perforated. There were 14 arteries where the procedure was performed in a retrograde direction from the popliteal artery.7 In these 14 arteries, the residual patent lumen of the proximal superficial femoral artery was 30 cm), or they may perforate externally. (Reprinted with permission from Cardiovascular Reviews and Reports, Im.)
TABLE
I Comparison
of Clinical
Trials to Recanalize
Author
Technrque
Zeitler 1980 Marhn 1981
Mechanical
Krepel 1985 Hewes 1986
Balloon
Morganstern 1977-80 1981-88
Balloon Balloon
Occluded
Balloon
Balloon
Total
Balloon or laser probe Laser probe Heated
Tobis 1989 McGowan 1988 Leachman 1989 Tobis Present 1991
Laser probe Heated Laser probe Heated Laser probe Heated Balloon
Femoropopliteal
Arteries Percent Primary Success
1 Year Patency of Pts. with 1” Success (%I
No. of Arteries
Occluded Length (cm)
304 133 46
82 53 76
NA NA 57
18 19 18 10 13 59 46
10 NA (mean 4 cm in 1” success group) 3 l-3 4-7 >7 NA l-20
89
93
26
83 74
50 81 100 91 82 NA
70
l-10
91
NA
86 69 100 70 66 73 67
NA NA 93 76 58 72 40
5.6 2 3.1
93
NA
20
< 10 > 10 14.2 + 6.9
80 50 95
NA NA 60
20
16.6
75
50
Thermal Levy 1989 Sanborn 1988
Superficial
14 13 17 37 53 Total 107 17 15 Total 117
Angioplasty
Studies NA NA 7 9.6 10.9
t 7.2
series Laser probe Cold (15) Hot (5)
t 9.7
NA = not available.
,
83% for occlusions 15 to 45 cm long, with an overall mechanism of recanalization proceeds along the perimprimary success rate of 85%. It is difficult to compare eter of the plaque, was used advantageously. Instead of different clinical studies because some reports combine terminating the procedure once the dissection plane was patients who have stenoses with those who have com- observed, it was used to burrow around the plaque until plete occlusions. In addition, the length of occlusion or the distal lumen could be reentered by tearing into it how the lengths are subdivided varies between the re- from the perimeter. It is ironic that in the attempt to ports. Some of the frequently cited clinical trials for find a better method than mechanical recanalization, recanalization of occluded superficial femoral arteries our experience with laser-assisted thermal angioplasty are presented for comparison in Table I for both me- lead to refinements in technique that improved the rechanical and thermal angioplasty. sults with standard mechanical balloon angioplasty. Earlier nonrandomized laser studies used historical This experience reemphasizes how the use of historical control groups to claim that mechanical balloon angio- control groups may be misleading. plasty has a limited primary success rate in occlusions This randomized trial demonstrates that the laser>3 cm and certainly >7 cm. However, a recent re- assisted probe is not superior to the results with stanport l l and the current study demonstrate a higher rate dard guidewire manipulation to reopen occluded superof primary success using mechanical guidewires and ficial femoral arteries. In addition, this study indicates supportive catheters. The high rate of success in the that the predominant effect of the laser probe appears present series of recanalizing long occluded segments of to be due to the mechanical component of the probe the superficial femoral artery is attributed to the alter- and not laser-induced heat. The blunted bullet-shaped native approaches used: either retrograde from the pop- contour of the laser probe was well designed to peneliteal artery or the combined anterograde and retro- trate atheroma. This penetration occurs around the obgrade punctures. In addition, the observation that the struction between the internal elastic membrane and LASER ANGIOPIASTY
1085
the plaque. Once in this dissection plane, it is more likely that the thermally active 2OO’C metal tip will perforate laterally through the thin media and adventitia. Thermal activation of the probe added successfully to the mechanical effect of the device in only 2 of 20 (10%) patients assigned to the laser group. This meager additional benefit does not appear to justify the large cost of current laser devices. The fact that 30,000 cases of laser-assisted thermal angioplasty have been performed without a randomized trial raises serious concerns about the scientific foundation on which decisions of treatment are made in interventional procedures with new devices.r2-l4
REFERENCES 1. Moretti M, Pearson T (eds.). Patient Data Supports Laser Angioplasty Efficacy. Medical Laser Industry Report (suppl) April 1990: l-4. 2. Lee G, Ike& RM, Chan MC, Lee MH, Ring JL, Reis RL, Theis JH, Low R, Bommer WJ, Kong AH, Hanna ES, Mason DT. Limitations, risks and complications of laser angioplasty: a cautious approach warranted. Am I Cardiol 1985;56:181-185. 3. Lee G, Ike& RM, Theis JH, Chan MC, Stabbe D, Ogata C, Kumagai A, Mason DT. Acute and chronic complications of laser angioplasty: vascular wall damage and formation of aneurysms in the atherosclerotic rabbit. Am d Cardiol 1984;53:290-293.
1086
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
4. Sanborn TA, Faxon DP, Haudenschild CC, Ryan TJ. Experimental angioplasty: circumferential distribution of laser thermal energy with a laser probe. J Am CON Cardiol 1985;5:934-938. 5. Lee G, Ikeda RM, Chan MC, Dukich J, Lee MH, Theis JH, Bommer WJ, Reis RL, Hanna ES, Mason DT. Dissolution of human atherosclerotic disease by fiberoptic laser-heated metal cautery cap. Am Heart J 1984;107:777-778. 6. Cumberland DC, Sanborn TA, Tayler DI, Welsh CL, Guben JK, Moore DJ, Greenfield AJ, Ryan TJ. Percutaneous laser thermal angioplasty: initial clinical results with a laser probe in total peripheral artery occlusion. Lancet 1986;l: 1457-1459. 7. Leachman R, Avedissian MG, Krajcer Z, Angelini P. Transluminal laser angioplasty of the femoropopliteal circulation by use of a percutaneous poplitcal approach. Am J of Cardioi 1989;64:106-108. 8. Tobis J, Smolin M, Mallery J, MacLeay L, Johnston WD, Connolly JE, et al. Laser-assisted thermal angioplasty in human peripheral artery occlusions: Mechanisms of recanalization. d Am CON Cardiol 1989;13:1547-1554. 9. Sanborn TA, Cumberland DC, Greenfield AJ, Motarjeme A, Schwarten DE, Leachman SR, et al. Peripheral laser-assisted balloon angioplasty. Arch Surg 1989;124:1099-1103. 10. Tobis JA, Miranda CP, Deutsch L-S, Griffith J, Gessert J, Bergman A, Berm M, Henry WI. The mechanism of peripheral recanalization by laser-assisted thermal angioplasty: confirmation by intravascular ultrasound. AJR 1990;155: 1100-1102. 11. Morgenstern BR, Getrajdman GI, Laffey KJ, Bixon R, Martin EC. Total occlusions of the femoropopliteal artery: high technical success rate of conventional balloon angioplasty. Radiology 1989;172:937-940. 12. Strandness DE, Barnes RW, Katzen B, Ring EJ. Indiscriminate use of laser angioplasty (editorial). Radiology 1989;172:945%946. 13. Society of Cardiovascular and Interventional Radiology. SCVIR position statement on thermal laser angioplasty. (editorial response) Radiology 1989; 172944. 14. Sanborn TA, Greenfield AJ. Peripheral laser angioplasty: need for organized clinical trials. (editorial response) Radiology 1989;172:943.
OCTOBER
15. 1991
![recanalization catheter system in arterial occlusions].](/assets/img/hold.png)
